There are various principles hitherto for knee protection devices. On the one hand, systems are known in which a padded plate is moved toward the knees of the occupant in the case of restraint, in order to prevent them from moving. On the other hand, there are knee protection devices with tubular gas bags which in the case of restraint emerge from the instrument panel and extend in front of the knees of the occupant, so that the knees lie directly against the gas bag (and not against a padded plate) and are restrained by the gas bag. In the second system which relates to the present invention, however, there are some disadvantages. Thus the restraining effect of this system depends very much on the size of the contact surface of the gas bag to the occupant. When the knees plunge into the gas bag, the internal pressure of the gas bag increases. However, if the contact of the occupant takes place over a very small area, only a small volume of gas can be displaced, so that the pressure rise in the airbag is very small. This effect is additionally amplified in that the airbag bulges out at different places when the knees plunge into it, which leads to a reduction to the change in volume and reduces the pressure increase. With a small pressure increase, however, only smaller restraining forces are able to be achieved. A further disadvantage relates to the application of the restraining force on the vehicle occupant. In the conventional system, a large part of the force is not introduced into the knee, as required, but rather into the shin bones, because in the case of restraint the occupant lies against the gas bag over a large part of the shin bones up to the knees. The biomechanical reasons (risk of injury) the introduction of force into the shin bones must be minimized.